This project proposes to identify patterns of EEG activity associated with performance on information processing tasks of proven sensitivity to schizophrenic dysfunction. Two tasks will be used, the Span of Apprehension (Span), an index of the efficiency of visual information processing, and the Continuous Performance Task (CPT), a measure of vigilance. These tasks are sensitive to acutely disturbed and partially recovered schizophrenic adults, and children who are actively schizophrenic or at risk. Event related EEG potentials (ERPs) will be recorded while subjects are performing these tasks. Temporal components of the ERP associated with different aspects of information processing will be examined to provide evidence concerning those aspects of cognitive processing affected by schizophrenia. Multivariate statistical analyses along with the use of an extensive array of electrodes (for mapping the topographic distribution of the scalp ERP activity) will permit inferences about brain systems underlying performance. A recently completed pilot study utilzing a Principal Components Analysis of ERP data along with ANOVA and SWDA techniques reveals differences between schizophrenic and normal children not only in performance but also in ERPs. Diminished amplitude and delays in the onset and resolution of the CNV as well as decreased amplitude of the N1 component in the schizophrenic group imply difficulties in the mobilization and direction of selective attention. Both CNV and N1 how different patterns of lateralization in the two groups. Second, there is an impairment of those processes underlying the identification of significant stimuli (the "P3" component) in the schizophrenics. A pilot study with younger normal children shows that the deficits seen in schizophrenic children are not merely a function of developmental delay. Grant support is requested to: 1) test large groups of subjects to confirm pilot results, 2) to run groups of younger normals to assess maturation effects, 3) to test for the specificity of these findings by using a contrast group showing another form of attentional impairment (attention deficit disorder), and 4) to purchase additonal recording and amplifying equipment to identify regional differnces in the ERPs with greater resolution to provide clues concerning the brain systems underlying information processing impairment in schizophrenia.